AD 59-10-05
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 981TC18EA1 | HAMILTON STANDARD Governors |
| aircraft | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA1 | HAMILTON STANDARD Governors |
| aircraft | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA2 | HAMILTON STANDARD Governors |
| aircraft | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA3 | HAMILTON STANDARD Governors |
| aircraft | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA4 | HAMILTON STANDARD Governors |
| aircraft | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA5 | HAMILTON STANDARD Governors |
| aircraft | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA6 | HAMILTON STANDARD Governors |
| aircraft | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Governors | HAMILTON STANDARD Governors |
| appliance | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 981TC18EA1 | HAMILTON STANDARD Governors |
| appliance | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA1 | HAMILTON STANDARD Governors |
| appliance | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA2 | HAMILTON STANDARD Governors |
| appliance | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA3 | HAMILTON STANDARD Governors |
| appliance | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA4 | HAMILTON STANDARD Governors |
| appliance | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA5 | HAMILTON STANDARD Governors |
| appliance | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Double Row Turbo Cyclone 988TC18EA6 | HAMILTON STANDARD Governors |
| appliance | Curtiss-Wright/Marquette, Inc. | Hamilton Standard | Governors | HAMILTON STANDARD Governors |
Unsafe Condition
Adverse environmental conditions in the propeller governor resulting from certain types of engine failure have caused improper operation of the governor in such a manner as to result in propeller overspeeding and failure to feather.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Replace the 5U21 governor with the Hamilton Standard 5AB23 governor or any other approved means to provide a means for feathering independent of the pilot valve.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
at first governor overhaul after September 1, 1959, but not later than February 1, 1960
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
All Hamilton Standard Propellers Controlled by 5U21 Governors and Installed on TC18EA Series Engines.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Governors.
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_59-10-05.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 59-10-05 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: HAMILTON STANDARD Governors Subject: Governors. Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Curtiss-Wright/Marquette, Inc. | Hamilton Standard Model: Double Row Turbo Cyclone 981TC18EA1 | Double Row Turbo Cyclone 988TC18EA1 | Double Row Turbo Cyclone...Show more Product Type: Appliance Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 59-10-05 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 59-10-05 SUBJECT HEADING: HAMILTON STANDARD Governors ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 59-10-05 HAMILTON STANDARD: Applies to All Hamilton Standard Propellers Controlled by 5U21 Governors and Installed on TC18EA Series Engines. Compliance required at first governor overhaul after September 1, 1959, but not later than February 1, 1960. Adverse environmental conditions in the propeller governor resulting from certain types of engine failure have caused improper operation of the governor in such a manner as to result in propeller overspeeding and failure to feather. In order to minimize the possibility of such occurrences, provide a means for feathering that will be independent of the pilot valve incorporated in the 5U21 governor. Replacement of the 5U21 governor by the Hamilton Standard 5AB23 governor is considered an acceptable means to accomplish the desired objective. Any other approved means of accomplishing the desired objective will also be acceptable. (Hamilton Standard Service Bulletin No. 591 covers this same subject.) FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_59-10-05.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 59-10-05 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: HAMILTON STANDARD Governors Subject: Governors. Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Curtiss-Wright/Marquette, Inc. | Hamilton Standard Model: Double Row Turbo Cyclone 981TC18EA1 | Double Row Turbo Cyclone 988TC18EA1 | Double Row Turbo Cyclone...Show more Product Type: Appliance Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 59-10-05 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 59-10-05 SUBJECT HEADING: HAMILTON STANDARD Governors ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 59-10-05 HAMILTON STANDARD: Applies to All Hamilton Standard Propellers Controlled by 5U21 Governors and Installed on TC18EA Series Engines. Compliance required at first governor overhaul after September 1, 1959, but not later than February 1, 1960. Adverse environmental conditions in the propeller governor resulting from certain types of engine failure have caused improper operation of the governor in such a manner as to result in propeller overspeeding and failure to feather. In order to minimize the possibility of such occurrences, provide a means for feathering that will be independent of the pilot valve incorporated in the 5U21 governor. Replacement of the 5U21 governor by the Hamilton Standard 5AB23 governor is considered an acceptable means to accomplish the desired objective. Any other approved means of accomplishing the desired objective will also be acceptable. (Hamilton Standard Service Bulletin No. 591 covers this same subject.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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